The incidence of treated End Stage Renal Disease (ESRD) is the rise in the United States. The diagnosis of this disease has disastrous implications for an individual's quality of life and probability of survival; treatment costs our nation 4.4 billion dollars a year. The relationship between severe forms of hypertension and renal disease is well-established but the risk of ESRD at lower blood pressures is uncertain. We propose to study the association of blood pressure (BP) with ESRD over a wide range of diastolic and systolic BP in middle-aged persons screened for the Multiple Risk Factor Intervention Trial (MRFIT) (325,384 white men; 36,278 black men) and for the Hypertension Detection and Follow-Up Program (HDFP) (53,750 white men; 64,008 white women; 15,269 black men; 25,437 black women). Additional questions that will be addressed include: 2) Is the higher rate of hypertensive ESRD reported in blacks compared to whites due to greater severity and/or duration of hypertension? 3) Are smoking and serum cholesterol concentration also positively associated with ESRD incidence? 4) Do cardiovascular risk factors measured prior to ESRD influence the survival rate after diagnosis of ESRD? 5) Is the underlying, diagnosis of hypertensive ESRD assigned in the Medicare Registry consistent with levels of blood pressure and diagnosis of hypertension measured prior to the development of ESRD? and, 6) Are there persons with ESRD who are denied access to renal replacement therapy? Since July, 1973, treatment for ESRD has been reimbursed through the Medicare ESRD program. Using a prospective study design, subjects who have developed ESRD since the inception of the MRFIT and HDFP cohorts in 1973-75 will be identified by linkage of the baseline data with the Medicare ESRD Registry. Persons who die of renal disease without renal replacement therapy will be detected by ongoing mortality surveillance in both cohorts. The feasibility of this extremely cost-effective approach and the ability of our group to work together has been demonstrated. Age-race-sex specific incidence rates for the development of ESRD will be calculated at <2, 2-3, 4--5 and >5 years of follow-up for various levels of blood pressure, serum cholesterol and cigarettes smoked per day. The association of these measurements with the later development of ESRD will be examined using cross-tabulation and regression methods to control for confounding variables. The results of this stud will lay the groundwork to develop primary prevention strategies to decrease both the burden of human suffering and ESRD health care costs.